f9c2648f54d452d0b99debd3880ba069 English dataset Molly Charlton Bibby HydroMap Ltd Graduate Geospatial Data Technician molly.charlton@bibbyhydromap.com pointOfContact 2020-03-31 MEDIN Discovery metadata standard 2.3.8 urn:ogc:def:crs:EPSG::25831 2019_001_HKZ_I_II_Backscatter_Data 2020-03-31 publication 2020-01-31 creation 2020-03-31 revision 2019_001 Bibby HydroMap were commissioned in February 2019 by Vattenfall Wind Power Limited to undertake a geophysical survey of the Hollandse Kust Zuid I and II Offshore Wind Farms (HKZWFZ I and II). The HKZWFS I covers an area of 67.2 km2, although the effective area available for HKZWFS I is 56.5 km2 when the maintenance zones for infrastructure (active cables and one planned telecom cable) are included. HKZWFS II covers an area of 47.7 km2. There is no active existing or planned infrastructure crossing the site. The Luchterduinen Wind Farm, commissioned late 2015 and operated by Dutch energy company Eneco, is located within the HKZWFZ. The 129 MW wind farm consists of 43 Vestas 3 MW V112 turbines, each with a tip height of 137 m. The objective of the survey was to acquire high resolution survey data to enable the development and construction of Hollandse Kust (Zuid) Wind Farm Sites. The survey data consisted of high-resolution geophysical data (including UXO survey) within specified areas around each proposed WTG location. Additionally, high resolution geophysical data was also acquired along proposed Inter Array Cable (IAC) routes. The survey is part of an overall strategy to reduce the UXO risk to ALARP, and to obtain detailed seabed data for engineering purposes. The survey is designed to provide information needed primarily for the following: - UXO survey for site clearance prior to construction - High resolution data set for engineering purpose and seabed mobility assessment prior to installation of wind farm assets Rachael Langan Bibby HydroMap Ltd Senior Hydrographic Data Processor dassh.enquiries@mba.ac.uk originator Vattenfall United Kingdom Vattenfall United Kingdom Vattenfall Wind Power Ltd Vattenfall United Kingdom mark.vadasz@vattenfall.com custodian notPlanned Marine Environmental Data and Information Network Oceanographic geographical features GEMET - INSPIRE themes, version 1.0 2008-01-06 revision Hydrography INSPIRE THEMES 2011-02-16 creation Acoustic backscatter in the water column SeaDataNet P021 parameter discovery vocabulary 2009-11-16 revision Not suitable for use in navigation otherRestrictions Not suitable for public distribution English oceans 4.0589 4.3940 52.3932 52.5505 2019-02-20 2019-10-25 Matt Shenton Bibby HydroMap Ltd matt.shenton@bibbyhydromap.com distributor dataset For all backscatter data processing and Angle vs. Range Analysis (ARA), Fledermaus Geocoder Toolbox (FMGT) was utilised. Preliminary data checks were conducted on board to assess data quality. The final processing and mosaic production were completed at the Bibby HydroMap office. The data for each survey area was loaded into FMGT with the databases and QPDs merged to a single GSF file in Qimera. This process utilised the QPD files created during the bathymetry processing and the raw QINSy database files containing backscatter data. Backscatter adjustments and filtering were undertaken by an automated process within the software, which applies specific parameters for Reson and Kongsberg backscatter data to create normalised data files ready for visualising in a single mosaic. With all data files normalised the resolution and size of the mosaic was defined. For this data the mosaic resolution was set to 1m. Due to the predefined survey blocks being too large for the computer’s memory to process mosaics at full resolution, mosaics were built based on survey line direction to ensure the highest quality of backscatter possible. Once these sections were created, they were adjusted to optimise the image and with a suitable range set were exported from FMGT. Blocks were loaded into FME where the whole site was normalised to ensure there was consistency across the survey area. Whilst processing the backscatter two issues arose. Banding was present across the site which caused some backscatter mosaics to have light and dark patches down single survey lines, this was due to an error in FMGT when processing the files and was easily fixed by manually changing the swath width in the software. The second issue was a lack of absorption value in some survey lines, this was found to be due to a bug in the Reson multibeam. This issue was fixed by overriding the absorption value with the correct value for the site, 110 dB.